
Suspention Problem ! Advice Please
#1
Posted 09 June 2014 - 02:44 PM
I am happy with it but when i carry a passenger or two at the back the back of the car seats low and the wheels rubbing on the arches... it is a nightmare!
the front of the car seems good and will not rub on the arches..
A friend of mine said that rubber cones are the best for Minis, and replace them asap !
But i am really happy with the ride of my car with coil springs, (driving alone or with 1 passenger on my side !) , the ride is soft absorbing bump stops and potholes !
The only problem is when i carry passengers , rubbing the rear arches.
I started thinking of replace only the rear coil springs with rubber cones.. and just stay with rubber cones at the back and coil springs at front, just to keep that smooth ride on the front and stop the rubbing at the back..
Has anybody done this ?
Please advice me as it is a nightmare to drive my mini with passengers right now !
Regards, Panayiotis
#2
Posted 09 June 2014 - 02:45 PM
#3
Posted 09 June 2014 - 02:55 PM
#4
Posted 09 June 2014 - 02:58 PM
Forgot to mention that i have Bilstein (yellow/blue ones)
Shock absorbers
#5
Posted 09 June 2014 - 03:53 PM
The spring rate of the Mini is quite critical as the springs have short travel. With rubber spring cones the suspension is true and correct 'rising rate'. With coil springs it is more difficult to get it right as the rate at which the spring rate increases is more difficult to get right. With coil springs for racing Minis, the idea was to use a high initial rate and thus reduce initial body roll to optimise cornering force on a smooth track. But for road use the initial rate must be lower and if it is slightly too low, then the suspension will compress and the wheel hit the arch, especially on the rear.
The best suspension for a road-going Mini is the original rubber cone springs as these are correct and really work well. Obviously what you have at present are too soft on initial rate, which is why the normal ride seems soft, but as soon as the rear seats are occupied the rear springs compress and that leaves insufficient travel for normal driving.
You have three choices:
1. Remove the rear springs and get a graph of load against deflection plotted, then find some new springs with a higher initial rate. You will need to do this at the front as well to keep the springs matched.
2. Raise the car and use adjustable dampers set a bit harder to reduce the bump compression rate when the rear is occupied. This may not cure the problem
3. Fit new rubber cone springs all round and have a permanent solution to the problem.
#6
Posted 09 June 2014 - 04:16 PM
My solution will not work ?
To just replace the rear coil springs with rubber cones ?
#7
Posted 09 June 2014 - 05:54 PM
No. fit the correct rubber cone springs all round, then the spring rate will be correct and 'as designed' for a road going Mini. Problem solved.
Coil springs were originally introduced to remove what might be termed 'free play' during the initial compression of the rubber cone suspension and to 'harden up' the suspension for better initial response in hard cornering on a track during racing and to reduce body roll at the ultimate limit.
It seems as though the coil springs offered for a smoother ride with a road car are, at best, a poor compromise. They can never better the design of the rubber rising rate cone springs. They might equal them if carefully designed and manufactured, but what advantage is that. You don't buy a classic Mini to get a modern car ride & feel.
#8
Posted 09 June 2014 - 07:13 PM
Going to sell the coil springs and buy a set of new rubber cones
#9
Posted 09 June 2014 - 07:15 PM
It might be worth mentioning, coil springs must be set up as per the suppliers instructions regarding ride height, deviate outside of that and you will for sure get problems of the nature you are experiencing. If you are using "soft" springs with lowered suspension what else can you realistically expect to happen?
Putting cone's in the rear only I would suggest is not advisable, but then again I have no experience of this.
#10
Posted 09 June 2014 - 08:25 PM
When the Mini was introduced one of the biggest selling advantages was the rubber cone suspension. No other car had fully independent suspension with true rising rate springs all round. Ford still had cart springs on the back of their new 997 Anglia. The motoring & technical media raved about how compliant the suspension was and how fantastic the road holding & handling were. There were explanations of how the initial spring compression was fairly soft, but not only got stiffer as the suspension compressed it, but the rate at which it got stiffer itself increased (i.e. 'rising rate').
It was/is a truly fantastic design and no coil spring will improve it in overall terms.
Maybe on a race car with very high initial spring rate the lap times will be slightly better on a really 'tight' circuit, but never for the road.
Soft & smooth a Mini is not going to be by modern standards, but take a look at the huge suspension travel of a modern small car like a Fiesta. It is simply huge.
If you want a really smooth ride, buy a Jaguar or a Mercedes, not a classic Mini. You can get a good Jag for £3000 .
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